Descriptions

In 2002, oxygen isotope ratios of water (H2
18O/H2
16O), dissolved barium, and salinity were
measured in surface waters around northern North America to identify freshwater sources and to
provide a large-scale background for interpretation of regional inputs and processes. Oxygen isotope
ratios showed that precipitation, river runoff, and sea ice meltwater were all significant contributors
to the freshwater carried by the coastal component of the Arctic throughflow. Precipitation and runoff
contributed 40% and 60%, respectively, to the freshwater found in surface waters along the
Pacific coast. Sea ice meltwater contributed up to 65% to waters residing near the Mackenzie River
and in the Canadian Arctic Archipelago. The salinity-barium relationship, after being corrected for
dilution by sea ice meltwater, indicated that freshwater from the Mackenzie River flowed eastward
into Amundsen Gulf. It did not, however, continue eastward through Dolphin Union Strait and
Coronation Gulf in 2002. In the eastern part of the Canadian Arctic Archipelago, Baffin Bay and the
Labrador Sea, barium concentrations in surface waters were low, the result of biological activity
and/or local freshwater inputs with low barium concentrations.